1. Field
The present application relates to an image processing device and an image processing program that process a color image.
2. Description of the Related Art
In order to accurately diagnose various diseases of animals including humans, diagnoses of pathological tissues and cells are indispensable. Among others, information about kinds, numbers and shapes of cells included in blood and bone marrow is indispensable in many diagnoses of diseases, and therefore, cells are collected from blood and bone marrow and specimens are prepared and then a technical expert observes differences in shapes and color tones of the cells using a microscope and judges the kinds and abnormalities of individual cells. Such tasks (in which a technical expert directly looks into a microscope and makes a judgment manually based on his/her own experience) are carried out routinely in an inspection room of hospitals all over the world.
On the other hand, with the recent development of digital technologies, each element of a microscopic image is converted into a digital element and an image can be not only directly projected on a screen but also processed in a variety of ways using software. If the task of judgment based on the experience of a technical expert is generalized into a method by which any one can make a distinction, it is made possible to considerably reduce the time and costs for the task.
In such circumstances, a color image of a stained specimen is taken in and pathological diagnoses of the specimen are made based on the image. It is common to identify the kinds of individual cells based on the differences in forms of specimen images that appear in the image (for example, refer to Non-patent document 1: Clinical & Laboratory Haematology, 2003, vol. 25, pp. 139-147, “Differential counting of blood leukocytes using automated microscopy and a decision support system based on artificial neural networks-evaluation of DiffMaster Octavia”). Instead of the diagnosis based on the differences in forms of specimen images, it is also proposed to identify the kinds of individual cells by plotting the values of each pixel of a color image of specimen in a predetermined color space and distinguishing between color differences for each kind of cells based on the sub-volume occupied by the values of each pixel in the color space (for example, refer to Patent document 1: Japanese Unexamined Patent Application Publication No. 2003-506796).
The method for distinguishing color differences for each kind of cells based on the sub-volume in the color space, is however an indirect method. In recent years, it is desired to directly distinguish between color differences for each kind of cells in a color image (real image) of specimen and make a diagnosis based on the color difference. However, the color difference for each kind of cells in a real image is extremely slight, and therefore, when a mixture of cells to be observed and cells other than those to be observed exists, there is a problem that it is difficult to distinguish the cells to be observed from cells other than those to be observed from the real image.